[tscs37]

That does not sound terrible useful.

For one, it'll only work if both sender and receiver use it. Which means for 99.99% of mail traffic right now, it is utterly meaningless.

edit: Plus you also literally wasted everyone's time and energy.

I'd rather favor some kind of mechanism like grey-lists that don't require sender opt-in otherwise it'll be a dead technology just like GPG. (You can probably count the number of GPG emails within 1000 average mails on one hand)

[amelius]

How about sending (by email) a link to a proof-of-work-website, so the hash function can be computed in javascript/wasm in a browser?

Anyway, I agree on the waste of time+energy.

[Sir_Cmpwn]

We make incremental change. Adoption starts slow, then some middle players pick it up, one big player grabs it and then it proliferates. I've been working on a mail client for some time and I have plans to write a mail server, and both will have first class, opt-out support for hashcash.

[tscs37]

That sounds like a lovely pipe-dream.

I severely doubt any big player picks it up on grounds of it being cheaper and less energy intensive to simply greylist or blacklist.